SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce8ba69bca7ac752bee28acb799509412aee12dca17598394a2c5991f372036' 
  AND token = 'NbgDtdfEA3/EhARXHpIgW5sqjTMemfl/MijaX02IglA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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