SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17f3bc00f21beceedda4cc8fb72016ea54fbb48d45e55683687132e31de15f55' 
  AND token = 'y0xTLFfBBujHrx+N3j/ffmJAonPgr7vVPXfp5ij0myA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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