SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b46808123e3b0a76dcccced91c5b1bdafe4399a764bf1c7e16ccf5bf3b710a9' 
  AND token = 'xi5bLicbsC6HqFjuwtbksPxSly5fGEkaDGPJFc3z7CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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