SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f017c31dac274babfb741282d8255b78fc437f6e0d8f97981b3dc275fe2a00d6' 
  AND token = 'LfGssqn9eb+OcVWgolq9OsWEz2DPsvIYhx3B2QvLUpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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