SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddaa8a1a8ab0d53eca06d104f3abc9f04bcdce4d7b86de9304fbbd29b635d045' 
  AND token = 'bSxO9t0TnXKpI1CU2lQjydHiN8qinyuB/CO8RCiZbKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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