SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfb9a268b0b7afe209a303fb7813dbafbe9ebb124bf8449003e94c296bb81893' 
  AND token = 'YlFH21cxktTexOPyXRIcRq0wLHUTmPLlSZ1ZSA3Alt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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