SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ecf419c84ce4057df904b6f47a12dcae86668e87370928c21ef4229af8f59fb' 
  AND token = 'D5Qa+wXhzB0BIthqnpcc/CNix1vpklHg+4uAwELyCfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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