SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14df1fb61c420d38cff8ac66dcbb7f4e8080c3dcc96140c9249076524dfc775f' 
  AND token = 'NUGrpxYxFnGHIiGnXg1+sLocvnKLXDG94nzUiaG4CEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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