SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32dcd16a4191fc24dbe3c33a8f0db690d5be03f0606493aac92455cbbfa95724' 
  AND token = 'n56WdIVkjAJuTGQtWsUwhwa4cCZLz3fhmOHhJoMSds8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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