SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08b33da65b9ad3686b134e6ac30d4022dfbf5945d2da608fe525aac3875241e1' 
  AND token = 'C2fNSUf5hWRkklGAyqgS371/SwJhWY3K1BpIyZvQfUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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