SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec5d0bbe019694df6971dc20cbd7dafa72433fc9988cd573795372befd11419a' 
  AND token = 'QPTiBMkk8QuAGRyMU7nOXhMrqWBCwQcWhCsfNUJn7Tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}