SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f869889c27a04051ee9a05b6e47d71469bde6dd1d4c8e0d84fb1eb329bbd8c1' 
  AND token = 'nvJfzB+B4Tq8ZQyNHwewiGp7FyDl95WiZUApSfDb4sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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