SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e81b62dc562c8f7bdceb827d76e7f0d3df2dbfa94ac888bde10875d8b7770cc' 
  AND token = 'e6WHPZh6S3aIvpvtabBEUmzaD1mIsDfeNLa3/G1QJJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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