SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be403ba0e696b644f18f77f554a5fd26686f04bf01fb6c283485f8ff71088260' 
  AND token = '8KGNZFxBKNGqtjLJr4lzmyEfuejKZDjOp7uaf1PUcoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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