SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a25770f144e377777386b6490b3b4a7e2966eb68df3fde367fb0cf13c8925019' 
  AND token = 'Do/uzGLSbYuZmDTsGnq/2g9euNhffB0jX+zgNygzcTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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