SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86e0afd5ad676ea652879d8ba858148dc98f2964f3415ad5b7fb9adea4c0c713' 
  AND token = 'sObQF4uu+819zF1pwEKtALGn6D2e9sarGTdxKA5U6iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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