SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c64caaf5ab9a202ca7360e313fea0e9921766f731a59187f7ca6de6705f984b' 
  AND token = 'YxTd/BuNIOoKjT9bZDhXK5I8tn+F6+USACut7UIcxM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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