SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35550bacaa80ab17dbacaf949acf9030459a4e0c17e837cebfbbd3ae61a2f48' 
  AND token = '4LaaTnT5eIx5mqJhGQUviogC9ROoWlS9ij3eQYKgT9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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