SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d71e1c209ff70a6088ef6c11f91797434d8a9f6ea45f30b30ecc8f90f9c7f07' 
  AND token = 'P8hVkr0wuxMlm7tvn88g9AuHad8FoiiQebCYKS5oQQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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