SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4535a0dd23531b86b9015f7e74418b9233e76aac21bf08d71d987824951ad876' 
  AND token = 'KZM9oAz/MD5j7TiwPS3hsP6y/u1nLNlTpfEUQGSyFOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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