SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b348089bd1f34eabf70bff535b629334fa455fecd341bfaee8ba0462d4c13308' 
  AND token = 'MkASCez40ARf4nc8oItkRqIST0rxxnoX9NVCl6uMprU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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