SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65feb8c8e91236d94469549df23669a26ca6a6dd3e638d249b5bb116fc8d55e7' 
  AND token = '/BSbv/CLZW+iy3iHUGw0MqSgJT5PtuO8jdWOSlhg73s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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