SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec25769ad4135fd94ada588c58c617054991613b6b94f3194ca51569973ee4f7' 
  AND token = 'SEmldBlPW6TDCnKPS/iUDg5MxzNnJip3THaqGhkDsN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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