SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c546820797976d9a9d664a990e23ad4e98e744fb34a3b8eb5ce84a6576a6732a' 
  AND token = 'pkKjdnCLosMxY0k1FcoZ2zv+ZUjBzHWK69o/8+/2gT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}