SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1343583cec2472539d203678b68ad7545b8dde22dbe3fe4f9873c2ec76d383d' 
  AND token = 'C3HVlDJq1AyT7BYJGqW/vUv1WQyZVhMwhjt3NdQWR9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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