SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9f84987d2c36e2104ff7178501421a760925406768f582604e97555a6b6b490' 
  AND token = '2x9sh3ZV+XgsUj0WHPvJ6YJCWk2s6pp/7F7jcXmPe2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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