SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97b961699b42e71c1562ecec4bd0a51be7090dd45bbebb64c9f4b1e21b382cb' 
  AND token = 'YYV5CUeIsVOrBnCGZ2l4wl4obZEtbzlF6bg6xWTY6Xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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