SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '704c22b4717629240bb7cbc64893861b00417c11573f8f723ca091de4e900348' 
  AND token = 'vMrc/KPVlIWZmDn1X4KJlg6zIYNrI2hVRYuwAv2Ia6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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