SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43cc24297755a55cdb2840f49ae1656bbb6227d035bc74ce2b28a53f2f11ca3a' 
  AND token = 'fJbwfQ1+qbfrwY3hj225QGYjOxva6uJZ9UMQ9mtzYE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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