SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b33f8273ae008bf374861b1dd784d261b6b9614269c770362188faac2c196fd0' 
  AND token = 'Er34EwlwCG0G3TXniGfEzAprIMhN4yStH4t8V6UcVpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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