SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f62df1b264f3bdf209cc99afc39ce042e1bf03ffd767278d15ef7374b8af614' 
  AND token = 'vV+TuE9RyEeZUBWApdufK9N8HPPBDyAotrBZhYHAYvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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