SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8de1fbc41a706273b46856354934b65a34c9ac1efcd47b18d8efe090e82363cc' 
  AND token = 'V+5uUiCQ07iRUHIIzVeNZQHDuwAEp0loOqSJJa5L3T0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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