SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1fdd12536c804960b1b02069528806168e65cebcb25bbb3e5312be44cec6ae' 
  AND token = 'pGhIXmxBqORg9tc7ot4Vm31Mi00uK0RUk7kXbEiGkQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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