SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3534b69f45d9fb52818c5e7dd5306b18f78a2dfcc5d25fa27efa249d3e32f6' 
  AND token = '65o8IOoRD9zRTRA4mEf5BycGWIHrzCWY5c5OHRT9JmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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