SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f50eea89a9c01625b279477cb36f7436e1294906517a34298498e0d3cc118a' 
  AND token = 'CJCGwCkNSHIqATRX8IifOH1HgT9Xio9TZTDEjWl4N5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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