SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a982d37897577f48a7167852ab13818851b475e9eab329dc3f90cf124c9b1f1' 
  AND token = 'gecv1is12vPZ4oaQMUQDdNgWT+FA9oDeueCl0KQNyRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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