SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbdc416114b043280f78ec3c18b4af56d4e5407a9ea156514c2dab17352d04a2' 
  AND token = '5mutRxJ31kXaWZ2rlD66dYZZZObNXEmlVuMRpCzmyEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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