SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d979754200c201df984571a23f4b7e67c402cdf64848f90ed805245c3f75e2' 
  AND token = '2ODfXke8FVphv5NybSjoleLxNmx7JlPdoIF1jIxh148=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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