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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9ebed615dbd22ca78fcf452ea1cd0699dbc5814e1aa44c2b519b8c2a26a559' 
  AND token = 'ZMfg2MSSGrEn+vTGAVt3jyAtRxf4GEYHTSDWHINrsd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}