SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a33463b17afa9ed5d42e906f627b5a73e82e1d396cbfb18017c0e4990176b102' 
  AND token = 'ub3QBZq//m8zDGAlnfuFL+RWSJ8x4blrfiG+RN7jCHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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