SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bde6f5873e2e46a1f0fbae0a9a7b96d23cb474d799144b4d7cb3afe205848c0c' 
  AND token = 'KAQhEcnQNHXN9nEyqA92QxlnlB4GoAuBfCnZp0zqG9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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