SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '466b3592a1684b6744188af7ceb1754336cce21fa04face407ff70b7ba5810b6' 
  AND token = 'eC+6KYvis4gRkalOeAYe1hVhj1JobsvcseydvbdgeYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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