SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371aaf444d7f0ce3066c4b58719decb75da7a6f8ea30958f73c3989db8b54d86' 
  AND token = 'wjv0/jhs8o9igNXtch2sr5wb1nKmuC0r9KscGYs+pCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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