SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07eda80ead919754dba4d659450247c53e522da3c2b53eff07cd268b0af43748' 
  AND token = 'pUebJqEhID6JdNgZxIoYC3OSfkrvecnUK7wPf+/J9Dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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