SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e15feb0bd49c2f84e2e4cfb31771231318ed674f2f9249781e141fa313102fdb' 
  AND token = 'yS8i8pal7BXludwG6yRBomU1k8fJ3A6l8qO5s40LNK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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