SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd37bb8e471e93b564ee711a6c21883037ac86b739c1dc8c28e62abaf8b1d6904' 
  AND token = 'x2gM4OoN707LXZWfUbvOmZXiadvDzPCplnCQSxCMzsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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