SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '700d1eb33a50bed90620bfc33cc5765051111fb6074692f24c75659dc8822925' 
  AND token = '6jgVDVmDN8vFz11GfPFEoWA/xH6xrUy2HKReLlQ8dsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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