SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b312bfe9a1b522d281212fc5bd1792896f7854de0c375c88813bfb6141eebfc' 
  AND token = 'ozcC/rmXpwQArXfqwb0995a22wqTKTgwBqLi3rV9zno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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