SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c739cd81dbcea3d8371cacb9c960de52d54ba2a83ca1ebf983407468c04a5573' 
  AND token = 'AfOH8LVHcoyEjFUz3tX4c02brQVuIqFcGuDHXR7Xjac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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