SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf37d4fd6847cd3fcc548e79179655464671dd4791da3629825f9a916f85f210' 
  AND token = 'nLwnnFbkv7HCU5fHzGg4jVZloK/AvhV5ioTcjLex1Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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