SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '893e187162a8a1d785b413727d83a7f598263a8481f652e786b3f2d0a29ad28b' 
  AND token = 'wCfkG2XVV+2xfQqHznhz2hR4anh6gRRI/2DQQafHySo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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