SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '661369989efb54f5569ff807aa8d15e9256c06351b143c4e825aae8b74d4bf9f' 
  AND token = 'yuYQrOy7YGwoEj/5K26bx9FsZ/+OBbtLDKBcZaXhcYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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