SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cbe5beebf536132b74d70ec84de171e00597f9a230903318d868beb9b9f28b6' 
  AND token = 'PoZpJmWov/QYhAMuZnurTBSj0J/KJNWvGHIaVj4wORY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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