SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f758099995bf4ee2ea3facfe37d93d2d0d7ca6bb1297737aba426e8b1951bc81' 
  AND token = 'tH+OsFxTt2jQyit/BZBNFOVOwSxtlEPy8tDluQhBh0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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