SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '953b03820e5cd274f5e19c9709abab862e45f0d66a37aafb22323ba971cb6c8f' 
  AND token = 'MFqXnl+G476BaRWxjFvJoo7l/IIkKrHI+CMKpKGzGJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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