SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2840d819313bd363de291251e3a5e5de74d64642a7786de88d9556f0b7253e5' 
  AND token = 'iQhkyc0FfOMvCIFWcHmmMHU7Kl/xoijzGiNgmO+qZ+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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