SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57bd39f848311e3582d76319a5ca47438da883a0d128e6b25fc0f7650af9aa1f' 
  AND token = 'syrXRbyMwIoqGJPbWOZhMw/L21uUemctP2nviECDZwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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