SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6dd07155d63a912dc2b814616ba752a56cb657966b0f10851995cbdb2df8099' 
  AND token = 'hHi5bOzD+02bX5ew4wcVI9V22biBIqCTCvp6ZiY7n/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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