SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e14d1774ca790d22eb7f8a9e1768e94116786fb67ce4f83e65012c0b98feb3' 
  AND token = 'phh1UC5BJBrbWmRv1YOKOgerGiI1/Ds8TtgpTpzGYFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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