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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ecbdf41d7bc7e3ff6d51603e299b94007ac8ed12b1caccf8f8d26a945804b21' 
  AND token = 'b5x4ukPhKXOXTbMg6/KWAfRdTLk7ljPXlpDAxtCV3GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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