SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edf4f5e2331e6dc87d6bb61830c192e9c0292cee1b66cb3589cdca771e39624e' 
  AND token = 'qvBl4yfasxfrJCr6dsmko/UZhf2DqWuBbXllFLGi6pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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