SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65d94631ba115e1da87aa259286deec5741d8485db23eea119f13e85840959d8' 
  AND token = 'AXmrIs+DEDn1vSYWk/VYrKfBYjDUAOa+PzvfmDOgWjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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