SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df00f1d8f9454bd1241097f9e969601f58ebf579bebd474bba6273011febaece' 
  AND token = 'Z+/Im5PWHZtqTLa/uqXqlkfxibiP7Dxxw8xN1GNqrxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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