SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e664911ee45587c4cb641ff856db04909646b9166cafe2e09546dd678f766a0' 
  AND token = 'Ys1jWbTxclkSClehmpzbR0kQUYf/FLH5tjhzyChF7ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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