SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0cdd8718436dd2d9b5620e0eb76b1b83a72a3df075a1ceacf600f28d5d9406' 
  AND token = 'zVSL7vp+DuuQizZQfRc5dISNbBJxweslUaG8vY+JjPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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