SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39ba910163a504ef0808b2f5fab347177ace14e63022c94d26328eaef67a5933' 
  AND token = 'B04b6Dc4GdvAG4o0vUanQevJVjHExupDKt/XfIYdGAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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