SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127f7bdf746368c7a4b9da62ff5fac34afeee56dc6b125348200d119807569ba' 
  AND token = 's/gvfhP030MXt7xU2ZDOjDgUwHdaoMTzQ2YhFLQmt+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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