SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2729a80d331736d2dc5a0ad095e0b7fa79708b3fce858459bf4fed6122eb2895' 
  AND token = 'UE/xf/uHVlBXvES5QvU3p2XT7NOZBh3lgVNVKfVqFkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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