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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8643eb72dd9b13ad1a1900c06de1bb3df1a499a1a5ecce8ab94c8b2d91f14cfc' 
  AND token = 'A1Z91Ouw7E+0zvbLpfO/OnHNUcmGRiCFAjCXRQ3Rabg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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